1. Field of the Invention
This present invention concerns a method for planning and/or monitoring an interventional high-frequency thermoablation, in which method 3D image data of a region of interest of a body are acquired with a tomographical imaging apparatus and are presented on an image display device so that a target area for the thermoablation as well as an extent of the target area are recognizable in one or more image presentations of the 3D image data. The invention also concerns a device for implementation of the method.
2. Description of the Prior Art
Interventional procedures are frequently supported by imaging techniques that enable a monitoring of the positioning of the instruments inserted into the body. Particular tomographical imaging methods such as computer tomography (CT) offer advantages both in the monitoring of the procedure and in the preceding planning based on the available 3D image data. For example, probes, biopsy needles or other medical instruments can be navigated to a specific target point in the body with the assistance of computer tomography. A special field of use is high-frequency (HF) thermoablation. In this technique, a needle-shaped applicator is penetrated into the body with local anesthetization and is pushed to the location of a tumor under CT monitoring. If the applicator is located in the target area, thermal energy is applied that leads to the destruction of the tumor tissue.
The extent of the ablated area depends on, among other things, the application duration as well as the power of the applicator. The applicator required for tumor ablation is normally determined in advance in a planning step. The tumor size and shape are thereby evaluated using CT image data that were acquired in advance from the region of interest of the body of the patient. After the user has determined the size of the tumor, he can select the applicator using data sheets and tables.
Modern ablation devices can measure the temperature and the impedance at the probe head during the ablation and therefore can control the ablation. An end point of the application can also be detected since the impedance normally drops off quite steeply when the tissue dies.
For the user, in the planning and during an intervention it is very difficult to estimate, by paging through an available 3D image data set, whether the target area which should be treated with the RF thermoablation is also sufficiently encompassed. This problem is present both in the planning phase and during the intervention. A particular difficulty is posed by larger tumors that cannot be treated with a single applicator position but rather in which the applicator must be brought to multiple ablation positions in succession in order to completely encompass the tumor.